1. Field of the Invention
The present invention relates generally to pumps and, more particularly, to a positive displacement pump which impels fluid through a series of annular chambers defined by multiple reciprocating annular rings.
2. Description of the Prior Art
It is known to pump fluid through a deformable member, such as a resilient tube, by compressing the tube to seal the flow path at a point and moving the point of compression axially along the tube to force fluid therethrough. While such tube pumps are valuable for metering precise amounts of fluid and for handling abrasive, toxic and other hard-to-handle fluids, such pumps are limited in that they can handle only a very low volumetric throughput at moderate temperatures and low pressures.
A particular problem has been encountered in pumping large volumes of fluids while minimizing suction vaporization defines the intake reliability of a pumping system. Sludge with entrapped air, hot or volatile fluids in a high speed system are prone to cavitate with attendant performance degradation. Conversely, a smaller mechanical system of equivalent fluid performance permits a greater strength to weight ratio. Thus, a positive, high capacity unit with a low net positive suction head requirement which can operate in a broad range of speeds and viscosities is desirable.